Conventional high-frequency antennas are often cumbersome to manufacture. For example, antennas designed for 100 GHz bandwidths typically use machined waveguides as feed structures, requiring expensive micro-machining and hand-tuning. Not only are these structures difficult and expensive to manufacture, they are also incompatible with integration to standard semiconductor processes.
As is the case with individual conventional high-frequency antennas, beamforming arrays of such antennas are also generally difficult and expensive to manufacture. Conventional beamforming arrays require complicated feed structures and phase-shifters that are impractical to be implemented in a semiconductor-based design due to its cost, power consumption and deficiency in electrical characteristics such as insertion loss and quantization noise levels. In addition, conventional beamforming arrays become incompatible with digital signal processing techniques as the operating frequency is increased. For example, at the higher data rates enabled by high frequency operation, multipath fading and cross-interference becomes a serious issue. Adaptive beamforming techniques are known to combat these problems. But adaptive beamforming for transmission at 10 GHz or higher frequencies requires massively parallel utilization of A/D and D/A converters.
The need for overhead intelligence, surveillance, and reconnaissance is growing in both civilian and military applications. Terrain obstacles (both urban and rural) make line-of-sight radio communication between legacy military radios problematic. A wireless repeater having beamforming capabilities would enable non-line-of-sight (NLOS) communication, thereby significantly enhancing signal fidelity and integrity. In addition, beamforming provides inherent resistance to signal jamming and multi-path interference. However, the aforementioned problems make conventional wireless repeaters costly and unreliable. Accordingly, there is a need in the art for improved beamforming wireless repeaters.